1. Field of the Invention
The present invention relates to a capsule endoscope apparatus which picks up an image of the body cavity.
2. Description of the Related Art
For example, U.S. Patent Publication No. 5,604,531 discloses, as one conventional art, an observing system of the interior of the body. According to the one conventional art, an image picked up by an image pick-up unit is extracorporeally transmitted by radio waves, is received by an extracorporeal device, and is stored. Then, the stored image is displayed and the position of the image pick-up unit is displayed.
Referring to FIG. 1, a capsule endoscope system 81 according to another conventional art comprises: a capsule endoscope apparatus 82 which is swallowed by a patient and which then picks up an image of the body cavity; and an extracorporeal device 83 which is extracorporeally arranged to the patient.
The capsule endoscope apparatus 82 comprises in a capsule container: illuminating means 84; an objective lens 85 which forms an image; image pick-up means 86 which is arranged at the image forming position and which picks up the image; and radio means 87 which transmits by radio waves an image signal picked up by the image pick-up means 86.
Further, the extracorporeal device 82 comprises: radio means 88 which receives the image signal transmitted by radio waves from the radio means 87 in the capsule endoscope 82; and recording means 89 which records the image signal that is demodulated by the radio means 88.
According to the other conventional art, referring to FIG. 2A, in the illuminating means 84, a white LED 93 is switched on/off at a predetermined interval via an electric switch 92 from a constant-current source 91, thus to emit light as shown in FIG. 2B.
In this case, a light-emitting amount L and a light-emitting time t are constant and the term is an image pick-up term T.
According to the conventional arts shown in FIGS. 1, 2A, and 2B, upon picking up an image of the body cavity, the distance from the capsule endoscope 82 to, e.g., the inner wall of the gastrointestinal tract as an observed target varies depending on the portion.
In this case, a light-emitting value of the illuminating means 84 which emits pulse light is constant, then, if the capsule endoscope is too much close to the observed target, the white compression is caused, and if it is too much apart from it, the black compression is caused.